Method of extruding viscose



Sept. 3, 1935.

E. o. FREUND METHOD OF EXTRUDING VISCOSE 5 Sheets-Sheet 1 Filed Nov. 4, 1935 5710676 0. yrezzzza? Sept. 3, 1935. E. o. FREUND METHOD OF EX TRUDING VISCOSE s sheets-shet 2 Filed NOV. 4, 1935 H wag/m Sept. 3, 1935. E. o. FREUND 2,013,491

METHOD OF EXTRUDING VISCOSE Filed Nov. 4, 1953 3 Sheets-Sheet I5 JZQWZZFW r'wirc 0. yrezzrzaz.

Patented Sept. 3, 1935 METHOD OF EXTRUDING VISCOSE Erwin O. Freund, Chicago, 1111., assignor to The 'Visking Corporation, Chicago, IlL, a corporation of Virginia Application November 4, 1933, Serial No. 696,731

2 Claims.

. This invention relates particularly to apparatus for producing artificial sausage casings, or the like. Such Casings are now being regularly manufactured by extruding viscose in the form of a seamless tube into a bath containing a coagulating agent and a regenerating agent.

It has been found that improved results can be obtained by employing a much deeper extrusion baththan was customary for many years. This enables the speed of production to be greatly improved, with consequent increase in output. For example, it has been found practicable to multiply the speed of extruding and drawing the tube 7 two or three times, without injury to the casing.

The primary object of the present. invention is to provide apparatus well adapted to the purpose of producing cellulose casings at a rapid rate.

The invention is illustrated-in a preferred embodiment in the accompanying drawings, in

which- Fig. 1 is a front elevational view of the improved extrusion apparatus; Fig. '2, a side elevational view of the same; Fig. 3, an enlarged front elevational view of a battery of extrusion tanks, partly in section; Fig. 4, 3. vertical sectional view taken as indicated at line 4 of Fig. 3; Fig. 5,, a plan view of the battery of tanks; Fig. 6, a brokenelevational view illustrating the overflow cups for the external bath, one of these cups appearing in section in Fig. 4; and Fig. '7, an enlarged broken vertical sectional view showing a detail of the connections between a door and door-frame employed in the construction of the several tanks. 7

In the illustration given, A designats'a frame which comprises vertical standards I, and crossbeams 2; B, a battery of tanks supported on the frame A, these tanks being preferably carried by the cross-members 2; B, a door removably applied to a wall of each tank 'of the battery some distance above the lower end thereof; C, an extrusion device connected with each one of the several tanks of the battery, each extrusion device having associated therewith a mandrel C and a drain pipe C D, a series of overflow cups, one of which is applied to the upper portion of each of the several tanks of the battery, the drainage of these cups being through tubes D' to a trough or receptacle -D having a drain pipe D which may lead to any suitable storage receptacle for collecting the overflow solution.

The tanks of the battery preferably are constructed of steel and provided with a lead lining. In the illustration given, the steel outer walls of the tanks are designated 3,'and the lead linings are designated 3 The front wall of each tank of the battery is provided with a door-opening 4 bounded by a steel frame 4 The lead lining is extended through the door opening and reflected over the frame 4 as indicated at 3 Preferably,

a bead of lead 3 (see Fig. 7) is applied to the The preferred manner of securing the doors in 15 position with a sealed joint is to equip the .marginal frame member with outwardly projecting threaded studs, or bolts 1, having nuts l applied thereto. The bolts, which may be of any desired number, extend through U-slots 8' with which the doors are provided at their margins. As will be: readily understood from Figs. 4 and '7, the doors may be pressed so firmly against the peripheral bead 3 of the door-frame as to form a liquid-tight seal. If desired, a slight looseness may be allowed in the hinge-connections of the doors to make sure that there will be nothing to prevent the tight clamping of the doors against their seats.

The battery of tanks may be securely mounted on the cross-bars 2 of the frame A in any desired manner. For example, these cross-bars may be welded to the outer steel sheets of the tanks.

The front wall of the battery preferably has secured thereto an inclined trough 9 which is disposed below the removable doors inposition to catch any drippings which may at any time come through the openings. The lower end of this trough communicates through a drain-tube 9 with the tank or vessel D The extruding device C may be of any suitable construction. In the illustration given, the extrusion-orifice is indicated at H), and a viscose casing is indicated at Ill bath in the tank is indicated at H. The fluid for the external bath enters the tank through a pipe l2; the viscose solution enters the extrusion device through the pipe l3; and the fluid for the internal bath enters through a pipe I4.

The mandrel C is hollow and serves as an overflow pipe for the internal bath. In the illustration given, the lower portion of the mandrel has fitted therein a disk or plug l5 having The height of the a central perforation which receives the upper 56 erably is equipped at its lower end (see Fig. 1) with a trap, or seal, l6, through which internally developed gases may escape. No claim to the use of such trap is made in the present application. It will suffice to state that by means of the trap a moderate internal pressure may be maintained within the casing, or tubing, which is being extruded and drawn upwardly through the extrusion-bath.

The overflow device D through which the external bath may overflow preferably is arranged in the manner illustrated in Fig. 4. I do not claim the construction of this device as my invention, although my invention does contemplate the use of any suitable overflow device for the escape of the external bath at the upper portion of the tank. I-Ieretofore, it has been customary to simply run an overflow pipe through a vertical wall near the upper end of the tank. It may be added that the extrusion device C is shown provided with a flange H which is secured by bolts 18 to a lead collar l9 which is formed integral with the lower portion of the lead lining 3 The collar l9 serves as a resistant lining for the inner margin of the central perforation 20 with which the bottom of the tank is provided.

In the use of the improved tank, the door B is withdrawn or removed, leaving the opening 4 uncovered. A suitable solution of a coagulating compound and a regenerating compound is introduced into the tank below the door-opening and the extrusion operation is started. At the outset, the viscose which is forced upwardly through the annular orifice ID coagulates in the form of a rather thick ring of viscous material over the external lip of the orifice at In. The operator, reaching through the opening 4, passes a finger between the lower portion of the mandrel and the ring of viscose and loosens the material from the inner lip of the extrusion orifice. At the same as the extrusion operation continues.

time, the thumb may be used to loosen the ring of viscous material from the external lip of the orifice. By careful manipulation, the operator is then able to draw the viscose casing upwardly Aft-er the viscose casing has been drawn upwardly to a point near the lower end of the opening 4, the operator then closes and bolts the door. The tank is then filled with the precipitating and regenerating solution to the level of the overflow,

- art.

and the casing is drawn upwardly through the tank and eventually passed over a large roller or the like, from which it may be conducted to a succession of baths, as well understood in the After the casing has been raised to the level of the door, continued filling of the tank and continued injection of the internal bath solution facilitate the raising of the tubing until it can be taken in hand at the upper end of the tank.

..- If desired, an instrument maybe used to grasp the tubing and draw it upwardly after it has first been elevated to the lower end of the opening 4.

The lower end of the opening 4 preferably is located about 21]" above the extrusion orifice, so

end of the drain-pipe C The drain-pipe C prefdepth of 48" or more, and it has been found that by employing a deep bath the speed of drawing of the casing may be more than doubled, even in dealing with the relatively heavy viscose casings.

Where smaller and lighter-walled casings are to be drawn, the bath may be much deeper. For example, in the case of very light-walled viscose casings, say of a diameter of up to 1 it is practicable to employ an extrusion bath having a depth of '72", or more. In the drawing of these latter casings, the speed may be increased threefold, or more, over the speed formerly employed in drawing the same casings in their relatively shallow baths.

Any suitable coagulating and regenerating compound may be employed in the bath. Preferably, a bath having a high acidity is employed, the purpose being to carry the regeneration of the viscose casing as far as possible in the extrusion tank, thus giving the gas which is generated within the viscose casing opportunity to escape rearwardly through the drain pipe C. In other words, it is preferred to approach rather closely a complete regeneration of the casing (conversion to cellulose) in the extrusion bath. A suitable composition for the extrusion bath is a solution comprising 8%-11% sulphuric acid and approximately 15% of sodium sulphate.

The cellulose casing, after emerging from the extrusion bath, may be dealt with in any desired manner for completing the regeneration, effecting purification by washing, effecting bleaching if desired, and finally passing through a very dilute solution of glycerine in water, and finally drying the casing. The glycerine serves as a softening agent. Being hygroscopic in character, it will attract moisture and serve to prevent the casing from becoming brittle. The drain trough 9 preferably is covered or lined with lead. As shown in Fig. 4, the lead lining of the tank may be reflected downwardly over the lower margin of the door-opening and then over the sheetsteel trough-member 9 The drain pipes are preferably of lead, also. Any suitable noncorrosive material may be employed as lining. It should be of such character that it will not be injured by the bath solution.

The foregoing detailed description has been given for clearness of understanding only, and no unnecessary limitations should be understood therefrom, but the appended claims should be construed as broadly as permissible, in View of the prior art.

What I regard as new and desire to secure by Letters Patent is:

1. In the manufacture of regenerated seamless cellulose tubing, a method for facilitating the drawing of such tubing through a relatively deep extrusion-tank having an annular extrudingdevice extending through the bottom of the tank and a mandrel rising therefrom, a lateral wall of the tankbeing provided, for the purpose, with a liquid-tight withdrawable door disposed a substantial distance above the bottom of the tank, said method comprising: extruding a plastic cellulose compound upwardly into the tank while said door is open and while the lower portion of the tank contains a coagulating and regenerating fluid, the extruded viscose forming initially a ring at the base portion of the mandrel; working said ring upwardly along the mandrel by hand-manipulation, the hand being inserted through said open door .and the lifting of the ring of viscose being facilitated by the bath, the

extrusion operation being continued; then closing the door and securing it in liquid-tight condition and raising the level of the bath to a higher point; and then continuing the lifting of the viscose ring by hand manipulation, the hand being inserted from a level higher than the level of said. door.

2. A method as specified in claim 1, in which the operation of manipulating and lifting said tubing is facilitated by an internal bath ejected from the base-portion of the mandrel and passing upwardly between the mandrel and said tubing.

ERWIN O. FREUND. 

